There are so many nice hacks in [Joekutz]’s retro LED display project that it’s hard to know where to start. There’s his DIY LED display controlled by an Arduino UNO. To have some text or picture for the display, he’s wired the output of a Bluetooth speaker directly to the Arduino, and sends it speaker tones that encode the text to draw. And as if that wasn’t enough, he’s hacked a quartz driver board from an analog clock to use the display as a clock as well.
Let’s start with the LED matrix display, perhaps the best excuse for trying your hand at shift registers. This display uses two such 8-bit shift registers daisy chained together feeding two 8-bit Darlington arrays. The display has ten rows of sixteen columns, and you guessed it, the columns are controlled by the sixteen shift registers. Two Arduino pins tell the shift registers which column to turn on. The rows are turned on and off using ten transistors controlled by ten more Arduino pins. Scanning at 80 frames per second he gets a nice, flickerless display.
To make both the LED matrix circuit board and the control board, [Joekutz] carved out isolation paths in copper clad boards using his homemade CNC mill. Be sure to check out the first video below to see his misadventures with it that ultimately led to his gorgeous boards.
Decorating graduation caps is often frowned upon by the administration but [Dan Barkus] is challenging his school authorities to keep from smiling when they see what he has in store. His build will dazzle the audience by mounting 1024 RGB LEDs in a 32×32 matrix on top of his cap, but hidden under the cap’s black cloth. When the LEDs are off he’s indistinguishable, and when he fires up the LEDs, shine through and put on a heck of a show. He can type messages on his phone to be displayed on the cap. He can even display images and animated GIFs.
The LED display can draw up to 4 amps at full white brightness so he picked up a USB battery with two output ports, one capable of 2.1 amps and the other 2.4 amps. He then hacked together a cable that has two USB connectors on one end, connected in parallel, and a DC jack on the other end. Altogether the battery bank is capable of up to 4.5 amps output combined out those two ports, meeting the LED display’s needs. The DC jack is plugged into the Teensy and all power goes through there.
One problem [Dan] had was that the Bluetooth module was booting up before the Teensy. It didn’t see the Teensy in time, causing the Bluetooth not to work. The solution he found is shown in the 2nd video embedded below. The fix powers the Bluetooth module separately, using a current limiting resistor and a capacitor to build up the voltage, delaying just long enough for the Teensy to win.
This massive LED display was assembled on a PVC banner (it can be rolled up!) measuring 2m by 1.5m, it boasts well over 6000 pixels, and as you can see from the photo — looks fantastic.
We recently published a post on How Many LEDs are Too Many, which spawned many comments showing off even more impressive displays with even higher LED counts. This is just one of them — and making it flexible as well? That’s just the icing on the cake.
To make the display flexible, [Elektric-Junkys] had a custom PVC banner printed with stripes to help them align 58 parallel strips of WS2811 LEDs on the surface.
[Stephen] designed a standalone Ambilight clone built around an FPGA and recently added many new features to make his design even better. His original design was based around a Spartan 3-E FPGA, but his new design uses the Papilio One board with a Spartan-6 LX9 FPGA. This gives him dedicated DSP hardware and more RAM, allowing him to add more processing-intensive features.
[Steven]’s new board can drive up to 4096 LEDs total, and each LED is colored from one of 256 segmented screen areas. The output of the LEDs is smoothed over a configurable time period which makes the result a bit more pleasant. [Steven] also added color correction matrices and gamma correction tables to make up for differences in LED coloration and so the output can be fine-tuned to the color of the wall behind the TV.
Finally, [Steven] added multiple configurations which can be stored in Flash memory. The FPGA can detect letterboxes and pillarboxes in the video stream and change to a corresponding configuration automatically, so settings rarely need to be manually adjusted. He also added an extensive serial interface to configure all of the parameters and configurations in Flash. Be sure to check out the video after the break to see his setup in action.
What better way to make a giant LED display than out of old empties and bottle crates? This is the Mate Light (pronounced Mah-Tay).
We were first introduced to the ever popular Club-Mate soda at one of the first hackerspaces we visited during our Hackerspacing in Europe Tour. It’s a soft drink produced in Germany, which seems to be the exclusive non-alcoholic drink of choice for almost all hackerspaces in Western Europe. The spaces in the Netherlands and Belgium would even make road trips to Germany just to load up a van with the drink to bring back home. Personally we didn’t really understand what was so special about it, but maybe we just didn’t drink enough!
Anyway, this impressive display makes use of 640 empties arranged in 4 rows of 8 crates for a decent 16 x 40 resolution. Each bottle is wrapped in aluminum foil and contains one RGB LED with a WS2801 driver. Each row of crates is connected to a TI Stellaris Launchpad, which has four hardware SPI interfaces — conveniently the number of rows of crates used! From there, an ancient ThinkPad T22 laptop runs the control program over USB to the microcontroller board. Their first software implementation used a Python script which was painfully slow — they’re now putting the finishing touches on using a C script instead.
Stick around to see the display in all of its awesomeness.
For some ungodly reason, [Scott] has a friend that wanted a ‘sexting themed’ Halloween costume. We won’t try to make any presumptions of the creativity or mental stability of [Scott]’s friend, but the SMS scrolling LED belt buckle he came up with is pretty cool.
The belt is based around a $13 scrolling LED belt buckle [Scott] found online. There was a problem with the belt buckle, though. Thirteen dollars means [Scott] didn’t get a whole lot of features with his buckle, so there are only 3 buttons on the entire device: letter up, letter down, and enter. Instead of pressing a button 80 times to get a lowercase ‘z,’ an Arduino was thrown into the mix to take care of all the button pressing.
The Arduino sketch could now input any message into the belt buckle in a matter of seconds. All that was left to do is taking care of the SMS to text part of the build. For this, [Scott] used the Sparkfun USB Host Shield and a custom Android app. Whenever an SMS is received on the phone, the message is sent through the USB shield to the Arduino and output on the belt buckle.
We won’t make any assumptions about the content of the messages during the Halloween party, but at least the video demo of the build is family friendly. Check it out after the break.